export function enter(callback){
	//定义回车事件
	if (document.addEventListener) { //如果是Firefox
		document.addEventListener("keypress", fireFoxHandler, true);
	} else {
		document.attachEvent("onkeypress", ieHandler);
	}
	function fireFoxHandler(evt) {
	
		if (evt.keyCode == 13) {
	
			 callback();
		}
	}
	
	function ieHandler(evt) {
	
		if (evt.keyCode == 13) {
			 callback();
		}
	}
}